Generating an alignment signal based on local alignment marker deformation

Abstract

A method for generating an alignment signal is described. The method includes detecting local dimensional distortions of an alignment mark, and generating the alignment signal based on the alignment mark. The alignment signal is weighted based on the local dimensional distortions of the alignment mark. Detecting the local dimensional distortions includes illuminating the alignment mark with radiation, the alignment mark including a geometric feature, and detecting one or more phase and / or amplitude shifts in reflected radiation from the geometric feature. The one or more phase and / or amplitude shifts correspond to one or more local dimensional distortions of the geometric feature. A parameter of the radiation, an alignment inspection site within the geometric feature, an alignment inspection site on a layer of a structure, and / or a radiation beam trajectory across the entire geometric feature can be determined based on the detected one or more phase and / or amplitude shifts.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 026,893, filed May 19, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The descriptions in this paper generally involve generating alignment signals based on local alignment mark deformation. Background Technology

[0004] Photolithography projection equipment can be used in the fabrication of integrated circuits (ICs). In such cases, a patterning apparatus (e.g., a mask) may include or provide a pattern (“design layout”) corresponding to a single layer of the IC, and this pattern can be transferred onto a target portion (e.g., comprising one or more dies) on a substrate (e.g., a silicon wafer) coated with a layer of radiation-sensitive material (“resist”) by methods such as irradiating the target portion through the pattern on the patterning apparatus. Typically, a single substrate comprises multiple adjacent target portions, and the pattern is transferred sequentially, one target portion at a time, by the photolithography projection equipment onto these multiple adjacent target portions. In one type of photolithography projection equipment, the entire pattern on the patterning apparatus is transferred onto a single target portion in a single operation. Such an apparatus is often referred to as a stepper. In an alternative apparatus (often referred to as a step-scanning apparatus), a projection beam scans over the patterning apparatus along an assumed reference direction (“scanning” direction) while the substrate moves synchronously parallel or antiparallel to the reference direction. Different portions of the pattern on the patterning apparatus are progressively transferred onto a single target portion. Because photolithography projection apparatuses typically have a reduction ratio M (e.g., 4), the rate at which the substrate is moved, F, will be 1 / M times the rate of the projection beam scanning pattern forming apparatus. Further information about the photolithography apparatus described herein can be found, for example, in US 6,046,792, which is incorporated herein by reference.

[0005] Before the pattern is transferred from the patterning apparatus to the substrate, the substrate may undergo various processes, such as primer coating, resist coating, and soft baking. After exposure, the substrate may undergo other processes (“post-exposure processes”), such as post-exposure baking (PEB), development, hard baking, and measurement / inspection of the transferred pattern. This array of processes is used as the basis for fabricating a single layer of a device (e.g., an IC). The substrate may then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., all of which aim to ultimately complete a single layer of the device. If multiple layers are required in the device, all processes or variations thereof are repeated for each layer. Ultimately, the device will exist in each target portion on the substrate. These devices are then separated from each other using techniques such as sawing or cutting, so that individual devices can be mounted onto carriers, connected to pins, etc.

[0006] Therefore, fabricating devices (such as semiconductor devices) typically involves processing a substrate (e.g., a semiconductor wafer) using multiple fabrication processes to form various features and multiple layers of the device. These layers and features are typically fabricated and processed using, for example, deposition, photolithography, etching, chemical mechanical polishing, and ion implantation. Multiple devices can be fabricated on multiple dies on a substrate and then separated into individual devices. This device fabrication process can be considered a patterning process. A patterning process involves patterning steps using patterning apparatus in a photolithography apparatus, such as optical and / or nanoimprint lithography, to transfer a pattern from the patterning apparatus onto the substrate, and the patterning process typically, but optionally, involves one or more associated patterning processing steps, such as resist development by a developing apparatus, baking the substrate using a baking tool, etching the pattern using an etching apparatus, deposition, etc.

[0007] As noted, photolithography is a central step in the fabrication of devices such as integrated circuits (ICs), in which patterns formed on a substrate define the functional elements of the device, such as microprocessors and memory chips. Similar photolithography techniques are also used in the fabrication of flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0008] As semiconductor manufacturing processes have continued to advance, over the past few decades, while the size of circuit elements has been steadily decreasing, the number of functional elements (such as transistors) per device has been steadily increasing, following a trend commonly known as "Mohr's Law." In the current state of technology, photolithography projection equipment is used to fabricate the layers of devices. This equipment uses illumination from a deep ultraviolet irradiation source to project a design layout onto a substrate, thereby forming individual functional elements with dimensions well below 100 nm (i.e., less than half the wavelength of radiation from the irradiation source, such as a 193 nm irradiation source).

[0009] The process of printing features smaller than the classical resolution limit of a photolithography projection apparatus is often referred to as low-k1 lithography, according to the resolution formula CD = k1 × λ / NA, where λ is the wavelength of the radiation used (currently mostly 248 nm or 193 nm), NA is the numerical aperture of the projection optics in the photolithography projection apparatus, CD is the "critical size"—typically the smallest feature size printed—and k1 is the empirical resolution factor. Generally, the smaller k1 is, the more difficult it becomes to reproduce patterns on the substrate that resemble the shape and size planned by the designer to achieve specific electrical functionality and performance. To overcome these difficulties, complex fine-tuning steps are applied to the photolithography projection apparatus, the design layout, or the patterning apparatus. These steps include, for example, but not limited to: optimization of NA and optical coherence settings, custom illumination schemes, the use of phase-shifted patterning apparatus, optical proximity correction (OPC, sometimes also referred to as "optical and process correction") in the design layout, or other methods generally defined as "resolution enhancement techniques" (RET). Summary of the Invention

[0010] According to an embodiment, a method for generating an alignment signal is provided. The method includes detecting one or more local dimensional deformations of an alignment mark and generating an alignment signal based on the alignment mark. The alignment signal is weighted based on the one or more local dimensional deformations of the alignment mark.

[0011] In an embodiment, detecting the one or more local dimensional deformations includes irradiating the alignment mark with radiation. The alignment mark includes a geometric feature. Detecting the one or more local dimensional deformations also includes detecting one or more phase and / or amplitude shifts in reflected radiation from the geometric feature. The one or more phase and / or amplitude shifts correspond to one or more local dimensional deformations of the geometric feature.

[0012] In an embodiment, the method further includes determining one or more of the parameters of the radiation, alignment check locations within the geometry, alignment check locations on layers of the structure, or radiation beam trajectories spanning the entire geometry based on the detected one or more phase and / or amplitude shifts.

[0013] In one embodiment, the geometric feature includes a grating.

[0014] In an embodiment, detecting one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature includes measuring the phase difference in the reflected radiation of different diffraction orders.

[0015] In an embodiment, generating the alignment signal includes: determining one or more regions of the geometry that are relatively more symmetrical than other regions of the geometry based on the detected one or more phase and / or amplitude offsets; and weighting one or more portions of the reflected radiation signal corresponding to radiation reflected from the relatively more symmetrical one or more regions more than other portions of the reflected radiation signal.

[0016] In one embodiment, the alignment mark is included in a layer of the substrate in the semiconductor device structure.

[0017] In one embodiment, the method further includes adjusting semiconductor device manufacturing parameters based on the alignment signal.

[0018] According to another embodiment, a non-transitory computer-readable medium is provided, having instructions on it. When executed by a computer, the instructions cause the computer to: detect one or more local dimensional deformations of an alignment mark; and generate an alignment signal based on the alignment mark. The alignment signal is weighted based on the one or more local dimensional deformations of the alignment mark.

[0019] In an embodiment, detecting the one or more local dimensional deformations includes: controlling the irradiation of the alignment mark, which includes geometric features; and detecting one or more phase and / or amplitude shifts in reflected radiation from the geometric features, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric features.

[0020] In an embodiment, the instructions also cause the computer to determine, based on the detected one or more phase and / or amplitude offsets, one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on the layers of the structure, or the radiation beam trajectory across the entire geometry.

[0021] In one embodiment, the geometric feature includes a grating.

[0022] In an embodiment, detecting one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature includes measuring the phase difference in the reflected radiation of different diffraction orders.

[0023] In an embodiment, generating the alignment signal includes: determining one or more regions of the geometry that are relatively more symmetrical than other regions of the geometry based on the detected one or more phase and / or amplitude offsets; and weighting one or more portions of the reflected radiation signal corresponding to radiation reflected from the relatively more symmetrical one or more regions more than other portions of the reflected radiation signal.

[0024] In one embodiment, the alignment mark is included in a layer of a substrate in the semiconductor device structure, and the instructions further enable the computer to adjust semiconductor device manufacturing parameters based on the alignment signal.

[0025] According to another embodiment, a system configured to generate an alignment signal is provided. The system includes: one or more sensors configured to detect one or more local dimensional deformations of an alignment mark; and one or more processors configured to generate the alignment signal based on the alignment mark. The alignment signal is weighted based on the one or more local dimensional deformations of the alignment mark.

[0026] In one embodiment, the system further includes a radiation source configured to irradiate the alignment mark with radiation, and detecting the one or more local dimensional deformations includes: irradiating the alignment mark, which includes geometric features, with radiation from the radiation source; and detecting one or more phase and / or amplitude shifts in reflected radiation from the geometric features, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric features.

[0027] In an embodiment, the one or more processors are further configured to determine one or more of the parameters of the radiation, alignment check locations within the geometry, alignment check locations on layers of the structure, or radiation beam trajectories spanning the entire geometry based on the detected one or more phase and / or amplitude shifts.

[0028] In one embodiment, the geometric feature includes a grating.

[0029] In an embodiment, detecting one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature includes measuring the phase difference in the reflected radiation of different diffraction orders.

[0030] In one embodiment, generating the alignment signal includes: determining one or more regions of the geometry that are relatively more symmetrical than other regions of the geometry, based on the detected one or more phase and / or amplitude shifts; and weighting one or more portions of the reflected radiation signal corresponding to radiation reflected from the relatively more symmetrical one or more regions more than other portions of the reflected radiation signal. In an embodiment, the alignment mark is included in a layer of a substrate in a semiconductor device structure.

[0031] In an embodiment, the one or more processors are further configured to adjust semiconductor device manufacturing parameters based on the alignment signal.

[0032] In one embodiment, a method for adjusting semiconductor device manufacturing parameters is provided. The method includes: detecting one or more local dimensional deformations of alignment marks; and generating an alignment signal based on the alignment marks, the alignment signal being weighted based on the one or more local dimensional deformations of the alignment marks, the alignment signal being configured to adjust the semiconductor device manufacturing parameters.

[0033] In one embodiment, the method further includes adjusting the semiconductor device manufacturing parameters based on the alignment signal.

[0034] In this embodiment, the semiconductor device manufacturing parameter is the platform position.

[0035] In an embodiment, detecting the one or more local dimensional deformations includes: irradiating the alignment mark, which includes a geometric feature, with radiation; and detecting one or more phase and / or amplitude shifts in reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

[0036] In an embodiment, the method further includes determining one or more of the parameters of the radiation, alignment check sites within the geometry, alignment check sites on layers of a semiconductor device structure, or radiation beam trajectories spanning the entire geometry based on the detected one or more phase and / or amplitude shifts. Attached Figure Description

[0037] The above and other aspects, as well as the features, will become apparent to those skilled in the art by reading the following description of the specific embodiments in conjunction with the accompanying drawings.

[0038] Figure 1 A photolithography apparatus according to an embodiment is schematically depicted.

[0039] Figure 2An embodiment of a photolithography unit or cluster according to an embodiment is schematically depicted.

[0040] Figure 3 An example inspection system according to an embodiment is schematically depicted;

[0041] Figure 4 An example measurement technique according to an embodiment is schematically depicted.

[0042] Figure 5 The figure illustrates the relationship between the irradiation spot and the measurement target of the inspection system according to an embodiment.

[0043] Figure 6 The figure illustrates a method for generating alignment signals according to an embodiment.

[0044] Figure 7 The figure illustrates an example of local dimensional deformation of geometric features in alignment marks according to an embodiment.

[0045] Figure 8 The figure illustrates a two-dimensional weighted graph of a portion of the radiation reflected from the alignment mark according to an embodiment, and an example radiation beam trajectory spanning the entire alignment mark.

[0046] Figure 9 The process of deriving multiple variables of interest based on measurement data according to an embodiment is illustrated schematically.

[0047] Figure 10 This is a block diagram of an example computer system according to an embodiment.

[0048] Figure 11 It is similar to the embodiments Figure 1 A schematic diagram of a photolithography projection device.

[0049] Figure 12 According to the embodiments Figure 11 A more detailed view of the device.

[0050] Figure 13 According to the embodiments Figure 11 and Figure 12 A more detailed view of the device's source collector module. Detailed Implementation

[0051] In semiconductor device fabrication, alignment determination involves determining the position of alignment marks (or multiple marks) within layers of the semiconductor device structure. Alignment is determined by irradiating the alignment marks with radiation and comparing the characteristics of different diffraction orders of the radiation reflected from the alignment marks. Typically, the alignment marks are treated as a whole for alignment determination. The determined alignment is usually based on an average value or the like, determined from the information conveyed by the radiation reflected from the entire alignment mark. For example, alignment can be determined based on a Fourier fit of the alignment signal as a function of the platform position (e.g., for platforms holding the semiconductor device structure).

[0052] However, alignment marks often exhibit local (intra-mark) dimensional distortions (e.g., deviations from the intended design dimensions), resulting in local alignment mark asymmetry. For example, the angle of a sidewall forming part of an alignment mark may be unintentionally tilted in a given area, and / or other local dimensional distortions may occur. Local alignment mark dimensional distortions and / or asymmetries are not considered during typical alignment determination. This can limit the accuracy of typical alignment determination.

[0053] Advantageously, this system and method reduce the impact of local alignment mark dimensional deformation on alignment determination, thereby improving the accuracy of alignment determination. The system and method are configured to detect local dimensional deformation of the alignment mark and to weight the alignment signal based on said local dimensional deformation. Local dimensional deformation is detected based on phase and / or amplitude shifts in radiation reflected from the alignment mark. The weighting is configured such that more symmetrical regions of the alignment mark have a greater impact on alignment determination than more asymmetrical regions (e.g., receiving a larger weight).

[0054] For example, this system and method are used to illuminate an alignment mark. One or more phase and / or amplitude shifts in the reflected radiation from the alignment mark are detected. The phase and / or amplitude shifts correspond to local dimensional deformations of the alignment mark. Based on the phase and / or amplitude shifts, portions of the reflected radiation signal corresponding to radiation reflected from relatively more symmetrical regions of the alignment mark (e.g., regions with little to no local dimensional deformation, as indicated by the lack of phase and / or amplitude shifts) are weighted more heavily than other portions of the reflected radiation signal. Alignment is determined based on the weighted signals, such that the lightly weighted portions of the signal corresponding to dimensionally deformed / asymmetrical regions of the alignment mark have little effect on alignment determination.

[0055] In brief, the descriptions in this document generally relate to semiconductor device fabrication and patterning processes. More specifically, the following paragraphs describe several components of the system and / or related systems, as well as methods for determining the relative positions of alignment marks in the layers of the structure. As described above, these systems and methods can be used, for example, to measure alignment during semiconductor device fabrication or other operations.

[0056] While specific references have been made to the fabrication of integrated circuits (ICs) herein, it should be understood that the description herein has many other possible applications. For example, it can be used in the fabrication of integrated optical systems, the guiding and detection of patterns in magnetic domain memories, liquid crystal display panels, thin-film magnetic heads, etc. Those skilled in the art will understand that, in the context of such alternative applications, any use of the terms “mask,” “wafer,” or “die” herein can be considered interchangeable with the more general terms “patterning apparatus,” “substrate,” and “target portion,” respectively.

[0057] As used herein, the term "projection optics" should be broadly interpreted to encompass various types of optical systems, including, for example, refractive optics, reflective optics, apertures or aperture stops, and reflective-refractive optics. The term "projection optics" may also collectively or individually include components that operate according to any of these design types for guiding, shaping, or controlling the projected radiation beam. The term "projection optics" can include any optical component in the lithography projection apparatus, regardless of its location on the optical path of the lithography projection apparatus. Projection optics can include optical components for shaping, adjusting, and / or projecting radiation from the source before the radiation passes through the patterning apparatus, or for shaping, adjusting, and / or projecting the radiation after the radiation passes through the patterning apparatus. Projection optics typically do not include the source or the patterning apparatus.

[0058] Figure 1An embodiment of a lithography apparatus LA is schematically depicted. The lithography apparatus includes: an irradiation system (irradiator) IL configured to modulate a radiation beam B (e.g., UV radiation or DUV radiation); a support structure (e.g., a mask stage) MT configured to support a patterning apparatus (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterning apparatus according to certain parameters; a substrate stage (e.g., a wafer stage) WT (e.g., WTa and WTb or both), configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate according to certain parameters; and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted by the radiation beam B by the patterning apparatus MA onto a target portion C (e.g., comprising one or more dies) of the substrate W. The projection system is supported on a reference frame RF.

[0059] As depicted, the device is of the transmissive type (e.g., employing a transmissive mask). Alternatively, the device may be of the reflective type (e.g., employing a programmable mirror array of the type mentioned above, or employing a reflective mask).

[0060] The irradiator IL receives a radiation beam from a radiation source SO. The source and the lithography apparatus can be separate entities, for example, when the source is an excimer laser. In this case, the source is not considered part or component of the lithography apparatus, and the radiation beam is transmitted from the source SO to the irradiator IL by means of a beam delivery system BD including, for example, suitable directional mirrors and / or beam expanders. In other cases, the source SO can be an integral part of the apparatus, for example, when the source is a mercury lamp. The source SO, the irradiator IL, and the beam delivery system BD, if necessary, can be collectively referred to as the radiation system.

[0061] The irradiator IL can modify the intensity distribution of the beam. The irradiator can be arranged to limit the radial range of the radiation beam such that the intensity distribution within an annular region in the pupil plane of the irradiator IL is non-zero. Alternatively, the irradiator IL can be operable to limit the beam distribution in the pupil plane such that the intensity distribution in a plurality of equally spaced sectors in the pupil plane is non-zero. The intensity distribution of the radiation beam in the pupil plane of the irradiator IL can be referred to as the irradiation mode.

[0062] Therefore, the illuminator IL may include an adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, at least the outer radial range and / or inner radial range (typically referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. The illuminator IL may be operable to change the angular distribution of the beam. For example, the illuminator may be operable to change the number and angular range of sectors in the pupil plane where the intensity distribution is non-zero. Different illumination modes can be achieved by adjusting the intensity distribution of the beam in the pupil plane of the illuminator. For example, by limiting the radial and angular ranges of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution can have a multipole distribution such as, for example, a dipole, tetrapole, or hexapole distribution. The desired illumination mode can be obtained by inserting an optics providing the illumination mode into the illuminator IL or by using a spatial light modulator.

[0063] The irradiator IL can be operable to change the polarization of the beam and can be operable to adjust the polarization using an adjuster AD. The polarization state of the radiation beam across the pupil plane of the irradiator IL can be referred to as a polarization mode. Using different polarization modes can allow for greater contrast in an image formed on the substrate W. The radiation beam can be unpolarized. Alternatively, the irradiator can be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam can vary across the pupil plane of the irradiator IL. In the pupil plane of the irradiator IL, the polarization direction of the radiation can be different in different regions. The polarization state of the radiation can be selected depending on the irradiation mode. For a multi-pole irradiation mode, the polarization of each pole of the radiation beam can typically be perpendicular to the position vector of the pole in the pupil plane of the irradiator IL. For example, for a dipole irradiation mode, the radiation can be linearly polarized in a direction substantially perpendicular to the line bisecting the two opposing sectors of the dipole. The radiation beam can be polarized in one of two different orthogonal directions, which can be referred to as X-polarization and Y-polarization states. For quadrupole illumination, the radiation in the sector of each pole can be linearly polarized in a direction substantially perpendicular to the line that bisects the sector. This polarization mode can be called XY polarization. Similarly, for hexapole illumination, the radiation in the sector of each pole can be linearly polarized in a direction substantially perpendicular to the line that bisects the sector. This polarization mode can be called TE polarization.

[0064] Additionally, the irradiator IL typically includes various other components, such as an integrator IN and a concentrator CO. The irradiation system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for guiding, shaping, or controlling radiation.

[0065] Therefore, the irradiator provides a regulated radiation beam B with desired uniformity and intensity distribution in its cross-section.

[0066] The support structure MT supports the patterning apparatus in a manner dependent on the orientation of the patterning apparatus, the design of the lithography equipment, and other conditions such as whether the patterning apparatus is held in a vacuum environment. The support structure can hold the patterning apparatus using mechanical, vacuum, electrostatic, or other clamping techniques. The support structure can be, for example, a frame or stage that can be fixed or moved as needed. The support structure ensures that the patterning apparatus is in a desired position, for example, relative to a projection system. Any term "mask" or "mask" used herein may be considered synonymous with the more general term "patterning apparatus".

[0067] As used herein, the term "patterning apparatus" should be broadly interpreted to refer to any apparatus capable of applying a pattern to a target portion of the substrate. In embodiments, a patterning apparatus is any apparatus capable of imparting a pattern to a radiation beam in the cross-section of the radiation beam to produce a pattern in the target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not correspond precisely to the desired pattern in the target portion of the substrate (e.g., if the pattern includes phase-shifting features or so-called auxiliary features). Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in the device being generated in the target portion of the device (such as an integrated circuit).

[0068] Pattern forming apparatuses can be transmissive or reflective. Examples of pattern forming apparatuses include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in photolithography and include mask types such as binary masks, alternating phase-shift masks, and attenuation phase-shift masks, as well as various hybrid mask types. Examples of programmable mirror arrays employ a matrix arrangement of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors impart a pattern to the radiation beam reflected by the mirror matrix.

[0069] As used herein, the term "projection system" should be interpreted broadly to include any type of projection system, including refractive, reflective, reflective-refractive, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation used or other factors such as the use of immersion liquids or vacuum. Any term "projection lens" used herein may be considered synonymous with the more general term "projection system."

[0070] The projection system PS may have a non-uniform optical transfer function, which could affect the pattern imaged on the substrate W. For unpolarized radiation, such an effect can be well described by two scalar maps, or scalar diagrams, that describe the transmission (aposification) and relative phase (aberration) of radiation leaving the projection system PS as a function of its position in its pupil plane. These scalar maps, which may be called transmission maps and relative phase maps, can be expressed as a linear combination of a complete set of basis functions. A convenient set is the Zernike polynomials, which form a set of orthogonal polynomials defined on the unit circle. Determining each scalar map may involve determining the coefficients in this expansion. Since the Zernike polynomials are orthogonal on the unit circle, the Zernike coefficients can be determined by successively calculating the inner product of the measured scalar map with each Zernike polynomial and dividing the inner product by the square of the norm of the Zernike polynomial.

[0071] The transmission mapping and relative phase mapping depend on the field and the system. That is, typically, each projection system PS will have a different Zernike expansion for each field point (i.e., for each spatial location in its image plane). The relative phase of the projection system PS in its pupil plane can be determined by performing PS on radiation (e.g., from a point source in the object plane of the projection system PS (i.e., the plane of the pattern forming device MA) and measuring the wavefront (i.e., the trajectory of points with the same phase) using a shearing interferometer. The shearing interferometer is an interferometer with a common path, and therefore, advantageously, no secondary reference beam is required to measure the wavefront. The shearing interferometer may include: geometric features in the image plane of the projection system (i.e., the substrate stage WT), such as a diffraction grating (e.g., a two-dimensional grating); and a detector arranged to detect an interference pattern in a plane conjugate to the pupil plane of the projection system PS. The interference pattern relates to the derivative of the phase of the radiation with respect to the coordinates in the shearing direction in the pupil plane. The detector may include an array of sensing elements (e.g., a charge-coupled device (CCD)).

[0072] The projection system (PS) of a photolithography apparatus may not produce visible fringes; therefore, phase-stepping techniques (such as, for example, moving a diffraction grating) can be used to enhance the accuracy of wavefront determination. Stepping can be performed in the plane of the diffraction grating and in a direction perpendicular to the scanning direction of the measurement. The stepping range can be one grating period, and at least three (uniformly distributed) phase steps can be used. Thus, for example, three scan measurements can be performed in the y-direction, each scan measurement performed for a different position in the x-direction. This stepping of the diffraction grating effectively converts phase changes into intensity changes, thereby allowing phase information to be determined. The grating can be stepped in a direction perpendicular to the diffraction grating (z-direction) to calibrate the detector.

[0073] The diffraction grating can be sequentially scanned in two orthogonal directions. These orthogonal directions can coincide with the axes (x and y) of the coordinate system of the projection system PS, or they can be angled (e.g., 45 degrees) to these axes. Scanning can be performed over an integer number of grating periods (e.g., one grating period). The scan averages the phase change in one direction, thereby allowing reconstruction of the phase change in the other direction. This allows the wavefront to be determined as a function of both directions.

[0074] The transmission (apodization) of the projection system PS in its pupil plane can be determined by PSing radiation (e.g., a point source in the object PS (i.e., the plane of the pattern forming apparatus MA) through the projection system PS and measuring the radiation intensity in a plane conjugate to the pupil plane of the projection system PS using a detector. The same detector used to measure the wavefront to determine the aberration can be used.

[0075] The projection system PS may include multiple optical (e.g., lens) elements and may additionally include an adjustment mechanism configured to adjust one or more of these optical elements to correct for aberrations (phase changes across the pupil plane throughout the field). To achieve this, the adjustment mechanism may be operable to manipulate one or more optical (e.g., lens) elements within the projection system PS in one or more different ways. The projection system may have a coordinate system in which its optical axis extends in the z-direction. The adjustment mechanism may be operable to perform any combination of: displacing one or more optical elements; tilting one or more optical elements; and / or deforming one or more optical elements. The displacement of the optical elements can be in any direction (x, y, z, or a combination thereof). By rotating about axes in the x and / or y directions, the tilt of an optical element typically deviates from a plane perpendicular to the optical axis, although rotation about the z-axis can be used for non-rotationally symmetric aspherical optical elements. The deformation of the optical elements may include low-frequency shapes (e.g., astigmatism) and / or high-frequency shapes (e.g., free-form aspherical surfaces). For example, deformation of an optical element can be performed by using one or more actuators for applying force to one or more sides of the optical element and / or by using one or more heating elements for heating one or more selected areas of the optical element. Typically, the projection system PS may not be able to be adjusted to correct apodization (transmission variation throughout the pupil plane). When designing a patterning apparatus (e.g., a mask) MA for a lithography apparatus LA, the transmission mapping of the projection system PS can be used. Using computational lithography, the patterning apparatus MA can be designed to at least partially correct apodization.

[0076] Photolithography equipment can have two stages (dual-platform) or more stages (e.g., two or more substrate stages WTa, WTb, two or more patterning apparatus stages, without a dedicated substrate stage WTa and stage WTb located below the projection system for purposes such as facilitating measurement and / or cleaning). In such a "multi-platform" machine, additional stages can be used in parallel, or preparation steps can be performed on one or more stages while one or more other stages are used for exposure simultaneously. For example, alignment measurements can be performed using an alignment sensor AS and / or level (height, tilt, etc.) measurements can be performed using a level sensor LS.

[0077] The photolithography apparatus may also be of the type in which at least a portion of the substrate is covered by a liquid (e.g., water) having a relatively high refractive index to fill the space between the projection system and the substrate. Immersion liquid may also be applied to other spaces within the photolithography apparatus, such as the space between the patterning apparatus and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of a projection system. As used herein, the term “immersion” does not mean that a structure such as a substrate must be immersed in a liquid, but rather that “immersion” simply means that the liquid is located between the projection system and the substrate during exposure.

[0078] In the operation of the lithography apparatus, the radiation beam is regulated and provided by the irradiation system IL. The radiation beam B is incident on a patterning apparatus (e.g., a mask) MA held on a support structure (e.g., a mask stage) MT and patterned by the patterning apparatus. Having passed through the patterning apparatus MA, the radiation beam B passes through the projection system PS, which focuses the beam onto the target portion C of the substrate W. The substrate stage WT can be accurately moved, for example, to position different target portions C within the path of the radiation beam B, using a second positioner PW and a position sensor IF (e.g., an interferometer, linear encoder, 2D encoder, or capacitive sensor). Similarly, for example, after mechanical retrieval from a mask library or during scanning, the first positioner PM and another position sensor (… Figure 1 (Not explicitly shown) This is used to accurately position the pattern forming apparatus MA relative to the path of the radiation beam B. Typically, the movement of the support structure MT can be achieved by means of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) that form part of the first positioner PM. Similarly, the movement of the substrate stage WT can be achieved using a long-stroke module and a short-stroke module that form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT may be connected only to the short-stroke actuator, or it may be fixed. The pattern forming apparatus MA and the substrate W can be aligned using pattern forming apparatus alignment marks M1, M2 and substrate alignment marks P1, P2. Although the illustrated substrate alignment marks occupy dedicated target portions, they can be located in the space between multiple target portions (these are called scribing alignment marks). Similarly, in cases where more than one die is disposed on the pattern forming apparatus MA, the pattern forming apparatus alignment marks M1, M2 can be located between these dies.

[0079] The depicted apparatus can be used in at least one of the following modes. In step mode, the support structure MT and substrate stage WT remain substantially stationary while the pattern applied to the radiation beam is projected onto the target portion C in a single exposure (i.e., a single static exposure). The substrate stage WT then moves in the X and / or Y directions, allowing different target portions C to be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scan mode, the support structure MT and substrate stage WT are scanned simultaneously while the pattern applied to the radiation beam is projected onto the target portion C (i.e., a single dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure MT can be determined by the (reduced) magnification and image inversion characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width of the target portion (along the non-scanning direction) in a single dynamic exposure, while the length of the scan motion determines the height of the target portion C (along the scanning direction). In another mode, the support structure MT remains essentially stationary to hold the programmable patterning apparatus in place, while the substrate stage WT is moved or scanned simultaneously as the pattern imparted by the radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically employed, and the programmable patterning apparatus is updated as needed after each movement of the substrate stage WT or between consecutive radiation pulses during scanning. This mode of operation can be readily applied to maskless lithography utilizing programmable patterning apparatuses such as programmable mirror arrays of the type described above.

[0080] Alternatively, the usage patterns described above or combinations and / or variations of completely different usage patterns can be adopted.

[0081] The substrates mentioned herein can be processed before or after exposure, for example in a track or coating development system (a tool that typically applies a resist layer to a substrate and develops the exposed resist), measurement tools, and / or inspection tools. Where applicable, the disclosure herein can be applied to such substrate processing tools and other substrate processing tools. Furthermore, the substrate can be processed more than once, for example to produce a multilayer IC, such that the term substrate as used herein can also refer to a substrate that already includes multiple processed layers.

[0082] The terms “radiation” and “beam” used in relation to photolithography in this article encompass all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., with wavelengths of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., with wavelengths in the range of 5 nm to 20 nm) as well as particle beams such as ion beams or electron beams.

[0083] Various patterns on or provided by a patterning apparatus can have different process windows, i.e., a space of processing variables (under which patterns will be generated within a specification). Examples of pattern specifications involving potential systematic defects include checks for necking, line pullback, line thinning, CD, edge placement, overlay, resist top loss, resist undercut, and / or bridging. Process windows for patterns on or in areas of the patterning apparatus can be obtained by merging (e.g., overlapping) the processing windows of each individual pattern. The boundary of a set of pattern process windows includes the boundary of the process windows of some individual patterns. In other words, these individual patterns limit the process windows of the set of patterns. These patterns may be referred to as “hot spots” or “process window limited patterns (PWLP)”, which are used interchangeably herein. Focusing on hot spots is possible and economical when controlling a portion of the patterning process. When the hot spot is defect-free, it is likely that other patterns are also defect-free.

[0084] like Figure 2 As shown, the lithography apparatus LA can constitute part or component of the lithography unit LC and is sometimes referred to as a lithography cell or cluster, and also includes equipment for performing one or more pre-exposure and post-exposure processes on the substrate. Typically, this equipment includes: one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing the post-exposure resist, one or more chillers CH, and / or one or more bakers BK. A substrate transport device or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves the substrates between different process units, and then transfers the substrates to the feed stage LB of the lithography apparatus. These units are often collectively referred to as a track or coating / developing system and are controlled by a track or coating / developing system control unit TCU, which is itself controlled by a TCU control system SCS, which in turn controls the lithography apparatus via the lithography control unit LACU. Therefore, different units can be operated to maximize throughput and processing efficiency.

[0085] To ensure that the substrate exposed by the lithography equipment is correctly and consistently exposed, and / or to monitor a patterning process (e.g., a device fabrication process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is desirable to examine the substrate or other object to measure or determine one or more properties, such as alignment, overlap (e.g., between structures in multiple overlapping layers, or between structures that have been separately set into the same layer by, for example, a double patterning process), line thickness, critical dimension (CD), focus offset, material properties, etc. Therefore, manufacturing facilities in which lithography units (LCs) are positioned typically also include a metrology system (MET) that measures the substrate W( Figure 1 The measurement system refers to some or all of the substrates that have been processed in the lithography unit or other objects within the lithography unit. The measurement system may be a part or component of the lithography unit LC, for example, the measurement system may be the lithography apparatus LA (such as an alignment sensor AS). Figure 1 Parts or components of ))

[0086] One or more measured parameters may include, for example, alignment, overlay between successive layers formed in or on the patterned substrate, critical dimensions (CD) (e.g., critical linewidth) of features formed in or on the patterned substrate, focusing or focusing error of the optical lithography step, dose or dose error of the optical lithography step, optical aberration of the optical lithography step, etc. The measurements may be performed on a target on the product substrate itself and / or on a dedicated measurement target set on the substrate. The measurements may be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0087] Various techniques exist for measuring structures formed during the patterning process, including the use of scanning electron microscopy, image-based measurement tools, and / or various specialized tools. As discussed above, a rapid and non-invasive specialized measurement tool is one in which a radiation beam is directed onto a target on the surface of the substrate, and the properties of the scattered (diffracted / reflected) beam are measured. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. Traditionally, this can be referred to as diffraction-based measurement. One such application of diffraction-based measurement is in alignment measurements. For example, misalignment can be measured by comparing portions of the diffraction spectrum (e.g., comparing different diffraction orders in the diffraction spectrum of a periodic grating).

[0088] Therefore, during or after a device fabrication process (e.g., a patterning process or a photolithography process), a substrate or other object may be subjected to various types of measurements. These measurements can determine whether a particular substrate is defective, can establish adjustments to the processes and equipment used in the process (e.g., aligning two layers on a substrate or aligning a patterning apparatus with a substrate), can measure the performance of the processes and equipment, or can be used for other purposes. Examples of measurements include optical imaging (e.g., optical microscopy), non-imaging optical measurements (e.g., diffraction-based measurements, such as the ASML SMASH measurement system), mechanical measurements (e.g., mapping using a stylus, atomic force microscope (AFM), and / or non-optical imaging (e.g., scanning electron microscope (SEM)). The SMASH (Smart Alignment Sensor Hybrid) system, as described in U.S. Patent No. 6,961,116 (the entire contents of which are incorporated herein by reference), employs a self-reference interferometer that generates two overlapping and relatively rotated images of an alignment mark, detects the intensity in a pupil plane (in which the Fourier transform of the images causes interference), and extracts position information based on the phase difference between the diffraction orders of the two images (which manifests as intensity changes in the order after interference).

[0089] Measurement results can be provided directly or indirectly to the management and control system (SCS). If an error is detected, adjustments can be made to the exposure of subsequent substrates (especially if inspection can be completed quickly enough so that one or more other substrates in the batch are still awaiting exposure) and / or to the subsequent exposure of the already exposed substrates. Furthermore, already exposed substrates can be stripped and reworked to improve yield, or discarded, thereby avoiding further processing of substrates known to be defective. If only some target portions of the substrate are defective, further exposure can be performed only on those target portions that meet specifications. Other manufacturing process adjustments are also taken into consideration.

[0090] The measurement system can be used to determine one or more property structures of the substrate, and in particular to determine how one or more properties vary between different substrates, or how one or more properties vary between different layers of the same substrate structure. The measurement system can be integrated into a lithography apparatus (LA) or a lithography unit (LC), or it can be a separate device.

[0091] To enable measurement, one or more targets are often specifically formed on the substrate. For example, targets may include alignment marks and / or other targets. In embodiments, the targets are specifically designed and may include periodic structures. In embodiments, the targets are part of a device pattern, such as a periodic structure of the device pattern. In embodiments, targets on the substrate may include one or more 1D periodic structures (e.g., geometric features, such as gratings) printed such that, after development, the periodic structure features are formed by solid resist lines. In embodiments, the targets may include one or more 2D periodic structures (e.g., gratings) printed such that, after development, the one or more periodic structures are formed by solid resist pillars or vias in the resist. Gratings, pillars, or vias may alternatively be etched into the substrate (e.g., etched into one or more layers on the substrate).

[0092] Figure 3 An example inspection system 10 is described, which can be used to detect alignment and / or perform other measurement operations. The example inspection system includes a radiation source projector 2 that projects or otherwise illuminates radiation onto a substrate W (e.g., the substrate W may include alignment marks). The redirected radiation is passed to a sensor that measures the spectrum (intensity as a function of wavelength) of specular reflection and / or diffracted radiation, such as a spectrometer detector 4 and / or other sensors, such as in… Figure 4 As shown in the curve on the left. The sensor can generate an alignment signal that transmits alignment data indicating the properties of the reflected radiation. Based on this data, it can be processed by one or more processors (PUs). Figure 4 (A general example is shown in the figure) or through other operations to reconstruct the structure or profile that produces the detected spectrum.

[0093] As in Figure 1 In a photolithography (LA) setup, one or more substrate stages can be provided. Figure 4 (Not shown) to hold the substrate W during measurement operations. The one or more substrate stages can be in form with... Figure 1The substrate stages WT are similar to or identical to the substrate stages. In an example where the inspection system 10 is integrated with a lithography apparatus, they can even be the same substrate stages. Coarse and fine positioners can be provided and configured to accurately position the substrate relative to the measurement optics. Various sensors and actuators are provided, for example, to obtain the position of the target portion of the structure of interest (e.g., alignment marks) and to position it below the objective lens. Typically, many measurements will be performed on the target portion of the substrate at different locations throughout the substrate W. The substrate support is movable in the X and Y directions to obtain different targets and is movable in the Z direction to obtain the desired location of the target portion relative to the focus of the optics. When, for example, in practice, the optics may remain substantially fixed (typically in the X and Y directions, but possibly also in the Z direction) and the substrate moves, it is convenient to consider and describe the operation as if the objective lens is being moved to different locations relative to the substrate. Assuming the relative positions of the substrate and the optical system are correct, it is in principle irrelevant which of the substrate and the optical system is moving in the real world, or both of them are moving, or a part of the optical system is moving (e.g., in the Z and / or tilt directions) and the rest of the optical system is fixed in combination with the substrate being moving (e.g., in the X and Y directions, and optionally in the Z and / or tilt directions).

[0094] For typical alignment measurements, the target (partial) 30 on the substrate W can be a 1D grating, printed such that after development, the grating strips are formed of solid resist lines (e.g., said solid resist lines may be covered by a deposition layer) and / or other materials. Alternatively, the target 30 can be a 2D grating, printed such that after development, the grating is formed of solid resist pillars and / or other features in the resist.

[0095] Bars, pillars, vias, and / or other features may be etched into or on the substrate (e.g., etched into one or more layers on the substrate), deposited on the substrate, covered by a deposition layer, and / or have other properties. Target (part) 30 (e.g., bars, pillars, vias, etc.) is sensitive to process variations during patterning (e.g., optical aberrations, focal length variations, dose variations, etc., in a photolithography projection apparatus in a projection system), such that these process variations manifest as variations in target 30. Therefore, measurement data from target 30 can be used to determine adjustments to one or more manufacturing processes, and / or as the basis for making actual adjustments.

[0096] For example, measurement data from target 30 can indicate the alignment of layers in a semiconductor device. The measurement data from target 30 can be used (e.g., by one or more processors) to determine one or more semiconductor device manufacturing process parameters based on the alignment, and to determine adjustments to semiconductor device manufacturing equipment based on the determined one or more semiconductor device manufacturing process parameters. In some embodiments, this may include, for example, platform position adjustments, or it may include determining adjustments to mask design, measurement target (e.g., alignment mark) design, semiconductor device design, radiation intensity, radiation incident angle, radiation wavelength, pupil size and / or shape, resist material, and / or other process parameters.

[0097] Angle-resolved scattering measurements are useful for measuring asymmetry in features within product and / or resist patterns. A specific application of asymmetry measurement is the measurement of alignment. For example, the use of angle-resolved scattering is described in U.S. Patent Application Publication US2006-066855. Figure 3 The basic concept of asymmetry measurement of System 10, the entire contents of which are disclosed in the aforementioned U.S. patent application, are incorporated herein by reference. In short, for alignment measurements, the positions of the diffraction orders in the diffraction spectrum of a target are determined by the periodicity of the target (e.g., alignment marks). Asymmetry in the diffraction spectrum represents the asymmetry of the various features constituting the target.

[0098] Figure 5 The diagram shows Figure 4 The system includes the extent of the illumination spot S and a planar view of a typical target (e.g., alignment mark) 30. Typically, to obtain a diffraction spectrum unaffected by surrounding structures, in embodiments, the target 30 is a periodic structure (e.g., a grating) larger than the width (e.g., diameter) of the illumination spot S. The width of the spot S may be smaller than the width and length of the target. In other words, the target is "underfilled" by the illumination, and the diffraction signal is substantially unaffected by any signals from product features, etc., other than the target itself. The illumination arrangement may, for example, be configured to provide illumination of uniform intensity across the entire back focal plane of the objective lens. Alternatively, the illumination may be restricted to an on-axis or off-axis direction, for example, by including apertures in the illumination path.

[0099] As described above, alignment is typically determined for the alignment mark as a whole. The determined alignment is usually based on information conveyed by radiation reflected from the entire alignment mark. However, alignment marks often have local (within the mark) dimensional deformations (e.g., deviations from the dimensions intended for the design), which creates local alignment mark asymmetry. For example, the angle of a sidewall forming part of the alignment mark may be unintentionally tilted in a given area, and / or other local dimensional deformations may occur. Local alignment mark dimensional deformations and / or asymmetries are not considered during typical alignment determination. This can limit the accuracy of typical alignment determination.

[0100] Conversely, this system and method reduce the impact of local alignment mark dimensional deformation on alignment determination, thereby improving the accuracy of alignment determination. The system and method are configured to detect local dimensional deformation of the alignment mark and to weight the alignment signal based on said local dimensional deformation. Local dimensional deformation is detected based on phase and / or amplitude shifts in radiation reflected from the alignment mark. The weighting is configured such that more symmetrical regions of the alignment mark have a greater impact on alignment determination than less asymmetrical regions (e.g., applying a larger weight).

[0101] Figure 6 The figure illustrates a method 600 for generating alignment signals. In some embodiments, generating alignment signals is performed as part of a semiconductor device manufacturing process. In some embodiments, for example, one or more operations of method 600 may be performed within... Figure 3 and Figure 4 System 10 in the diagram, computer system (e.g., such as...) Figure 10 Implemented in (as shown in and described below), or by Figure 3 and Figure 4 System 10 in the diagram, computer system (e.g., such as...) Figure 10 The method 600 can be implemented (as shown in the diagram and described below) and / or implemented in other systems or by other systems. In some embodiments, method 600 includes detecting 602 one or more local dimensional deformations of alignment marks, generating 604 the alignment signal based on the alignment marks, determining 606 adjustments for the semiconductor device manufacturing process, and / or other operations. Method 600 is described below in the context of alignment, but this is not intended to be limiting. Method 600 can generally be applied to many different processes.

[0102] The operation of method 600 presented below is intended to be illustrative. In some embodiments, method 600 may be implemented using one or more additional operations not described, and / or not using one or more of the operations discussed. For example, in some embodiments, method 600 does not need to include determining adjustments for the semiconductor device manufacturing process. Additionally, in Figure 6 The order of operations of method 600, as illustrated in the figure and described below, is not intended to be restrictive.

[0103] In some embodiments, one or more portions of method 600 may be implemented in and / or controlled by one or more processing devices (e.g., digital processors, analog processors, digital circuits designed for processing information, analog circuits designed for processing information, state machines, and / or other mechanisms for electronically processing information). The one or more processing devices may include one or more means for performing some or all of the operations of method 600 in response to instructions electronically stored on an electronic storage medium. The one or more processing devices may include one or more means configured by hardware, firmware, and / or software specifically designed to perform one or more operations of method 600 (e.g., see below with...). Figure 10 (Related discussions).

[0104] Operation 602 includes detecting one or more local dimensional deformations of the alignment mark. For example, the alignment mark may be included in a layer of a substrate in a semiconductor device structure. In some embodiments, the alignment mark includes geometric features, such as 1D or 2D gratings, and / or other geometric features. The principles of interferometry and / or other principles can be used to detect one or more local dimensional deformations of the alignment mark.

[0105] Detecting the one or more local dimensional deformations involves irradiating the alignment marks with radiation. The radiation may have a target wavelength and / or wavelength range, target intensity, and / or other characteristics. The target wavelength and / or wavelength range, target intensity, etc., may be entered and / or selected by the user, determined by the system based on previous alignment measurements, and / or otherwise determined. In some embodiments, the radiation includes light and / or other radiation. In some embodiments, the light includes visible light, infrared light, near-infrared light, and / or other light. In some embodiments, the radiation may be any radiation suitable for interferometric measurements.

[0106] The radiation can be emitted from a radiation source (e.g., Figure 3 and Figure 4The projector 2, shown in the diagram and described above, generates the radiation. In some embodiments, the radiation source may otherwise direct the radiation onto the entire alignment mark, sub-sections of the alignment mark (e.g., something smaller than the whole), and / or the alignment mark. In some embodiments, the radiation may be directed onto the alignment mark in a time-varying manner by the radiation source. For example, the radiation may be rasterized on the alignment mark so that different portions of the alignment mark are illuminated at different times. As another example, the characteristics of the radiation (e.g., wavelength, intensity, etc.) may vary. This may create a time-varying data envelopment or window for analysis. The data envelopment may facilitate / facilitate the analysis of individual sub-sections of the alignment mark, comparisons of one part of the alignment mark with another, and / or other analyses.

[0107] Detecting one or more local dimensional deformations of the alignment mark includes detecting one or more phase and / or amplitude shifts in reflected radiation from one or more geometric features of the alignment mark. The one or more phase and / or amplitude shifts correspond to one or more local dimensional deformations of the geometric features. For example, the phase and / or amplitude of reflected radiation from a deformed portion of the alignment mark's geometric features is different from the phase and / or amplitude of reflected radiation from an undeformed portion of the mark.

[0108] Figure 7 Examples 700 and 702 illustrate local dimensional deformations 704 and 706 of geometric features 708 and 710 in alignment marks 712 and 714. Both geometric features 708 and 710 include grating structures. Example 700 shows a side view of the grating structure / geometry 708. Example 702 shows a top view of the grating structure / geometry 710. Figure 7 As shown, geometric features 708 and 710 have symmetrical portions 720 without local dimensional deformation. However, geometric feature 708 includes a portion dimensional deformation 704, which includes unintentionally tilted sidewalls. For example, the tilted sidewalls do not match the angle of the opposite sidewalls in the grating, thus creating asymmetry. Geometric feature 710 includes a dimensional deformation 706, which includes sidewalls that have been unintentionally deviated from their intended location. For example, the sidewalls are not straight and do not match the straightness or flatness of the opposite sidewalls. As described above, one or more phase and / or amplitude shifts corresponding to the local dimensional deformations 704 and 704 of geometric features 708 and 710 will be detected in the radiation reflected from alignment marks 712 and 714.

[0109] return Figure 6Detecting one or more phase and / or amplitude shifts in reflected radiation from a geometric feature involves measuring local phase shifts (e.g., local phase increments) and / or amplitude changes corresponding to the local dimensional deformation. For example, reflected radiation from a specific region of an alignment mark may include a sinusoidal waveform with a specific phase and / or amplitude. Reflected radiation from different regions of the alignment mark (e.g., regions with dimensionally deformed geometric features) may also include sinusoidal waveforms, but with different phases and / or amplitudes. Detecting one or more local phase and / or amplitude shifts in reflected radiation from the geometric feature involves measuring the phase and / or amplitude differences in reflected radiation at different diffraction orders. For example, the Hilbert transform and / or other techniques can be used to detect the one or more local phase and / or amplitude shifts. Interferometry techniques and / or other operations can be used to measure the phase and / or amplitude differences in reflected radiation at different diffraction orders.

[0110] To detect local phase shifts, a Fourier transform (FFT) and a Hilbert transform are applied to each window (each window being one period of the signal). The real and imaginary parts of the signal are generated by the FFT and Hilbert transform. The signal phase is calculated as the arctangent of the imaginary / real ratio, where the amplitude is the magnitude of the imaginary / real part vector. The aligned signal exhibits local phase / amplitude variations in the signal. Compared to signals with local asymmetry, the diffracted signal has smaller local phase / amplitude variations.

[0111] Operation 604 includes generating the alignment signal based on the alignment mark. The alignment signal includes an electronic signal representing and / or otherwise corresponding to radiation reflected from the geometry of the alignment mark. The alignment signal may indicate, for example, the alignment value of the alignment mark, and / or other information. Generating the alignment signal includes sensing the reflected radiation and converting the sensed reflected radiation into the electronic signal. In some embodiments, generating the alignment signal includes sensing different portions of reflected radiation from different regions and / or different geometries of the alignment mark, and combining the different portions of the reflected radiation to form the alignment signal. This sensing and conversion may be performed by... Figure 3 and Figure 4 The detectors 4, 18 and / or processor PU shown are similar and / or the same components and / or other components used to perform the operation.

[0112] Generating the alignment signal based on the alignment mark involves identifying one or more regions of the geometric feature that are relatively more symmetrical or, conversely, have smaller dimensional deformations compared to other regions of the geometric feature. These regions are determined based on the detected one or more phase and / or amplitude shifts, and / or other information. For example, the detected phase and / or amplitude shifts in the reflected radiation correspond to local dimensional deformations in the geometry of the alignment mark (e.g., as described above). Figure 7 (Related description). The portion of reflected radiation without phase and / or amplitude shift, and / or with reduced phase and / or amplitude shift, corresponds to a region / geometric feature of the alignment mark that has no local dimensional deformation, and / or has minimal local dimensional deformation. In other words, the portion of reflected radiation without phase and / or amplitude shift, and / or with reduced phase and / or amplitude shift, corresponds to a symmetrical (non-deformed) region / geometric feature of the alignment mark.

[0113] In some embodiments, determining one or more regions of a geometry that are relatively more symmetrical, or conversely, have less dimensional distortion compared to other regions of the geometry may include directly measuring the dimensions of the alignment mark's geometry. For example, a scatterometer and / or other systems may be used to perform direct dimensional measurements of the alignment mark. In some embodiments, direct dimensional measurements may be used in conjunction with, and / or instead of, the local phase and / or amplitude offsets described herein to determine one or more regions of the geometry that are relatively more symmetrical, or conversely, have less dimensional distortion compared to other regions of the geometry. For example, the output dimensional measurement results from the scatterometer system may be provided to a processor PU (…). Figure 3 The processor PU and / or other system components may generate the alignment signal based at least in part on the output size measurement results from the scatterer system.

[0114] Operation 604 includes weighting the alignment signal. The alignment signal is weighted based on one or more local dimensional deformations of the alignment mark, and / or symmetrical / asymmetrical geometric features, and / or other information. One or more portions of the reflected radiation signal corresponding to radiation reflected from one or more relatively more symmetrical (smaller dimensional deformation) regions of the alignment mark are given greater weight than other portions of the reflected radiation signal. In some embodiments, one or more portions of the reflected radiation signal corresponding to radiation reflected from relatively more asymmetrical (larger dimensional deformation) regions of the alignment mark may be assigned little or no weight. Thus, when the different portions of the reflected radiation are combined into an electronic signal representing the reflected radiation, the alignment value indicated by the electronic signal is largely (and / or even entirely) based on radiation reflected from symmetrical (smaller dimensional deformation) regions of the alignment mark's geometry. An example of a weighting function could be, for example, inversely proportional to the intensity asymmetry (or amplitude asymmetry) of the measured positive and negative diffraction orders.

[0115] Operation 606 includes determining adjustments for the semiconductor device manufacturing process. In some embodiments, operation 606 includes determining one or more semiconductor device manufacturing process parameters. These parameters may be determined based on detected phase and / or amplitude asymmetry changes, alignment values ​​indicated by the alignment signal, dimensions determined by a scattering system and / or other similar systems, and / or other information. The parameters may include radiation parameters (radiation for determining alignment), alignment inspection sites within a geometry, alignment inspection sites on layers of the semiconductor device structure, radiation beam trajectories across the entire geometry, and / or other parameters. In some embodiments, process parameters may be broadly interpreted to include platform location, mask design, measurement target (e.g., alignment mark) design, semiconductor device design, radiation intensity (for exposing resist, etc.), radiation incident angle (for exposing resist, etc.), radiation wavelength (for exposing resist, etc.), pupil size and / or shape, resist material, and / or other parameters.

[0116] The radiation parameters used to determine alignment may include wavelength, intensity, angle of incidence, and / or parameters of the radiation. These parameters can be adjusted to better measure geometric features with a specific shape, enhance the intensity of reflected radiation, increase and / or otherwise enhance (e.g., maximize) the phase and / or amplitude shift in reflected radiation from one region of the alignment mark to the next (if any), and / or for other purposes. This can enable and / or enhance the detection of finer dimensional deviations, make phase and / or amplitude shifts easier to detect, and / or have other advantages.

[0117] In some embodiments, local phase and / or amplitude offsets, data from a scatterometer system and / or other similar systems, and / or other information can be used as key performance indicators for marking inter-mark variations and / or intra-mark variations (size deviations), and can be used to perform real-time marking, and / or selection of intra-mark geometric features. Alignment can be determined based on these selections.

[0118] For example, alignment check areas within a geometric feature may include specific portions of the geometric feature relative to other possible portions. These specific portions may include edges, corners, portions of lines, and / or other areas. These specific portions may be identified as being consistently more symmetrical (with less dimensional deformation or no deformation at all) relative to other portions, thus facilitating / facilitating more accurate alignment determination based on radiation reflected from that specific portion. For example, if a specific portion of the geometric feature is determined to be consistently more symmetrical based on detected phase and / or amplitude shifts, that specific portion of the geometric feature can be used across different alignment markers for alignment determination.

[0119] Alignment inspection sites on layers of a semiconductor device structure may include specific alignment marks relative to other alignment marks and / or other inspection sites. For example, if a specific alignment mark in a given layer is determined to be more symmetrical than other alignment marks in that layer based on detected phase and / or amplitude shifts (e.g., reflected radiation from the alignment mark includes smaller and / or less noticeable phase and / or amplitude shifts), then that specific alignment mark can be used to determine the alignment of that layer. Other, less asymmetrical alignment marks in the layer may or may not be used. For example, corresponding alignment marks may also be used to determine the alignment of subsequent layers.

[0120] The radiation beam trajectory across the entire geometry can include the path the radiation beam follows as it is rasterized across the entire alignment mark. The path can connect regions of the geometry / alignment mark that are relatively more symmetrical than other areas. The path can be an optimal route for measuring alignment across the entire alignment mark, avoiding large asymmetries. For example, the radiation beam can be controlled to avoid regions in the alignment mark where local dimensional deviations in the geometry are detected (e.g., based on local phase and / or amplitude shifts, ASML YieldStar output, and / or other information as described herein). For example, the radiation beam trajectory can be fed into a measurement system such as an ASML SMASH and / or Orion system.

[0121] In some embodiments, controlling the radiation beam to avoid detecting localized dimensional deviations in the alignment mark may include mapping dimensional deviations at different x and / or y positions across the geometry of the alignment mark (and / or across the entire alignment mark) to find an optimized (more symmetrical) measurement region. In some embodiments, this may include generating a two-dimensional weighted map for the portion of the radiation reflected from the alignment mark.

[0122] Figure 8 An example two-dimensional diagram 800 illustrates the alignment signal weights (e.g., determined as described above) of the portion of radiation reflected from the geometry of the alignment mark, and an example radiation beam trajectory 802 spanning the entire geometry / alignment mark. Different levels, or degrees, of shading are used to illustrate different alignment signal weights. Figure 8 In the diagram, region 804 illustrates the weights corresponding to the less asymmetrical (larger dimensional deformation) regions of the alignment mark. Region 806 illustrates the weights corresponding to the more symmetrical (smaller dimensional deformation) regions of the alignment mark. Figure 8 As shown, trajectory 802 connects to the alignment mark in region 806, which is relatively more symmetrical compared to other regions.

[0123] return Figure 6In some embodiments, operation 606 includes determining process adjustments based on the determined one or more semiconductor device manufacturing process parameters, adjusting the semiconductor device manufacturing equipment based on the determined adjustments, and / or other operations. For example, if the determined alignment is not within process tolerances, the misalignment may be caused by one or more manufacturing processes whose process parameters have drifted and / or otherwise changed so that the processes no longer produce acceptable devices (e.g., alignment measurements may violate an acceptability threshold). One or more new or adjusted process parameters may be determined based on the alignment determination. The new or adjusted process parameters may be configured to cause the manufacturing process to produce acceptable devices again. For example, the new or adjusted process parameters may cause previously unacceptable alignments (or misalignments) to be adjusted back into an acceptable range. The new or adjusted process parameters may be compared with existing parameters of a given process. For example, if a difference exists, that difference may be used to determine adjustments to the equipment used to produce the device (e.g., parameter "x" should be increased / decreased / changed so that it matches a new or adjusted version of parameter "x" determined as part of operation 606). In some embodiments, operation 606 may include (e.g., based on determined process parameters) electronically adjusting the device. Electronically adjusting the device may include sending electronic signals to the device, and / or other communications, which, for example, result in changes to the device. For example, electronic adjustment may include changing settings and / or other adjustments on the device.

[0124] Figure 9 An example process for determining adjustments (e.g., adjustments to parameters of a semiconductor device manufacturing process) based on measurement data obtained using metrology (e.g., alignment determined using this system and method) is schematically depicted. Radiation detected by detector 918 provides a measured radiation distribution 908 for a target (e.g., alignment mark) 930, which can be used to determine alignment, etc., as described herein. For a given target 930, radiation distribution 914, alignment, etc., can be calculated / simulated from a parametric model 906 using, for example, a numerical Maxwell solver 910. The parametric model 906 illustrates exemplary layers of various materials constituting and associated with the target. The parametric model 906 may include one or more variables for characteristics and layers of the target under consideration, which can be changed and derived. Figure 9As shown, the one or more variables may include the thickness t of one or more layers, the width w (e.g., CD) of one or more features, the height h of one or more features, and / or the sidewall angle α of one or more features. Although not shown, the one or more variables may also include, but are not limited to, the refractive index of one or more layers (e.g., real or complex refractive index, refractive index tensor, etc.), the extinction coefficient of one or more layers, the absorbance of one or more layers, resist loss during development, the footing of one or more features, and / or the line edge roughness of one or more features. The initial values ​​of these variables may be the expected initial values ​​of the target being measured. The measured radiation distribution 908, alignment, etc., are then compared with the calculated radiation distribution 912, alignment, etc., to determine the differences between them. If a difference exists, the values ​​of one or more variables of the parameterization model 906 can be changed, and the new calculated radiation distribution 912, alignment, etc., are calculated and compared with the measured radiation distribution 908, alignment, etc., until there is a sufficient match between the measured radiation distribution 908, alignment, etc. and the calculated radiation distribution 912, alignment, etc. At this point, the values ​​of the variables in the parameterized model 906 provide a good or optimal match to the geometry of the actual target 930. In an embodiment, a sufficient match exists when the difference between the measured radiation distribution 908, alignment, etc., and the calculated radiation distribution 912, alignment, etc., is within a tolerance threshold.

[0125] Figure 10 This is a diagram of an exemplary computer system CS that can be used in one or more of the operations described herein. The computer system CS includes a bus BS or other communication mechanism for communicating information, and a processor PRO (or multiple processors) connected to the bus BS for processing information. The computer system CS also includes a main memory MM (such as random access memory (RAM) or other dynamic memory), which is connected to the bus BS for storing information and instructions to be executed by the processor PRO. The main memory MM can also be used to store temporary variables or other intermediate information during the execution of instructions by the processor PRO. The computer system CS also includes a read-only memory (ROM) or other static storage device coupled to the bus BS for storing static information and instructions of the processor PRO. A storage device SD, such as a disk or optical disk, is provided and connected to the bus BS for storing information and instructions.

[0126] The computer system CS can be connected via a bus BS to a display DS for displaying information to the computer user, such as a cathode ray tube (CRT), flat panel display, or touch panel display. Input devices ID, including alphanumeric keys and other keys, are connected to the bus BS for communicating information and command selections to the processor PRO. Another type of user input device is a cursor controller CC (such as a mouse, trackball, or arrow keys), used to communicate directional information and command selections to the processor PRO and to control cursor movement on the display DS. This type of input device typically has two degrees of freedom on two axes (a first axis (e.g., x) and a second axis (e.g., y)), allowing the device to specify a position in a plane. Touch panel (screen) displays can also be used as input devices.

[0127] In some embodiments, portions of one or more methods described herein can be executed by a computer system CS in response to a processor PRO for executing one or more sequences of instructions contained in main memory MM. Such instructions may be read into main memory MM from another computer-readable medium, such as a storage device SD. Execution of the sequence of instructions contained in main memory MM causes the processor PRO to perform the process steps (operations) described herein. In a multiprocessor arrangement, one or more processors may also be used to execute the sequence of instructions contained in main memory MM. In some embodiments, hardwired circuitry may be used in place of or in combination with software instructions. Therefore, the description herein is not limited to any particular combination of hardware circuitry and software.

[0128] As used herein, the term "computer-readable medium" refers to any medium that participates in providing instructions to a processor (PRO) for execution. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical discs or magnetic disks, such as storage devices (SDs). Volatile media include dynamic memory, such as main memory (MMs). Transmission media include coaxial cables, copper wires, and optical fibers, including wires containing a bus (BS). Transmission media can also take the form of sound waves or light waves, such as those generated during radio frequency (RF) and infrared (IR) personal communications. Computer-readable media can be non-transitory, such as floppy disks, floppy disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tapes, any other physical media with a perforated pattern, RAM, PROMs, and EPROMs, FLASH-EPROMs, any other memory chips, or cassette memories. Non-transitory computer-readable media can have instructions recorded thereon. These instructions, when executed by a computer, perform any of the operations described above. For example, a temporary computer-readable medium may include a carrier wave or other means of propagating electromagnetic signals.

[0129] Various forms of computer-readable media can involve carrying one or more sequences of instructions to a processor PRO for execution. For example, the instructions may initially be carried on a disk of a remote computer. The remote computer may load the instructions into its dynamic memory and transmit them over a telephone line using a modem. A modem local to the computer system CS can receive data over the telephone line and convert the data into an infrared signal using an infrared transmitter. An infrared detector coupled to a bus BS can receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to main memory MM, from which the processor PRO retrieves and executes the instructions. The instructions received by the main memory MM may optionally be stored on a storage device SD before or after execution by the processor PRO.

[0130] The computer system CS may also include a communication interface CI connected to a bus BS. The communication interface CI provides bidirectional data communication to a network link NDL, which is connected to a local area network (LAN). For example, the communication interface CI may be an Integrated Services Digital Network (ISDN) card or modem for providing data communication connectivity to a corresponding type of telephone line. As another example, the communication interface CI may be a LAN card for providing data communication connectivity to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface CI transmits and receives electrical, electromagnetic, or optical signals carrying digital data streams representing various types of information.

[0131] A network link (NDL) typically provides data communication to other data devices via one or more networks. For example, a network link (NDL) can provide a connection to a host computer (HC) via a local area network (LAN). This can include providing data communication services via a global packet data communication network now commonly referred to as the "Internet" (INT). Both LANs (Internet) and HCs use electrical, electromagnetic, or optical signals to carry digital data streams. Signals carrying various network data and signals on the network link (NDL) and through the communication interface (CI) (which carries digital data to and from the computer system (CS)) are exemplary forms of carriers for transmitting said information.

[0132] A computer system (CS) can send and receive messages, including program code, via a network, network data link (NDL), and communication interface (CI). In the Internet example, the host (HC) transmits request code for an application via the Internet (INT), network data link (NDL), local area network (LAN), and communication interface (CI). For example, a downloaded application could provide all or part of the methods described herein. The received code can be executed by the processor (PRO) upon receipt and / or stored in storage device (SD) or other non-volatile memory for later execution. In this way, the computer system (CS) can acquire application code in carrier-like form.

[0133] Figure 11 An exemplary photolithography projection apparatus is schematically depicted, the exemplary photolithography projection apparatus being... Figure 1 The apparatus shown is similar to and / or identical to the techniques described herein. The apparatus 1000 includes an illumination system IL for adjusting a radiation beam B. In this particular case, the illumination system further includes: a radiation source SO; a first stage (e.g., a patterning apparatus stage) MT, the first stage MT being provided with a patterning apparatus holder for holding a patterning apparatus MA (e.g., a mask) and connected to a first positioner PM (operating in conjunction with a first position sensor PS1) to accurately position the patterning apparatus; a second stage (substrate stage) WT, the second stage WT being provided with a substrate holder for holding a substrate W (e.g., a silicon wafer coated with resist) and connected to a second positioner PW (operating in conjunction with a second position sensor PS2) to accurately position the substrate; and a projection system (“lens”) PS (e.g., a refractive, reflective, or reflective-refractive optical system) for imaging the illuminated portion of the patterning apparatus MA onto a target portion C (e.g., comprising one or more dies) of the substrate W.

[0134] As described herein, the device is of the transmissive type (e.g., employing a transmissive patterning apparatus). However, it can also typically be of the reflective type (i.e., employing a reflective patterning apparatus). The device may employ a different kind of patterning apparatus than a classic mask; examples include programmable mirror arrays or LCD matrices.

[0135] The source SO (e.g., a mercury lamp or excimer laser, LLP (laser-generated plasma) EUV source) generates a radiation beam. This beam is fed directly into the irradiation system (irradiator) IL, either directly or after passing through an adjustment device such as a beam expander Ex. The irradiator IL may include adjustment devices for setting the outer radial range and / or inner radial range (typically referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the beam. Additionally, the irradiator IL typically includes various other components, such as a beam accumulator IN and a condenser CO. In this way, the beam B incident on the pattern forming apparatus MA has a desired uniformity and intensity distribution in its cross-section.

[0136] about Figure 11 It should be noted that although the source SO can be located inside the housing of the photolithography projection device (which is often the case when the source SO is, for example, a mercury lamp), it can also be located away from the photolithography projection device, with the radiation beam it produces being directed into the device (e.g., by means of a suitable directional mirror); the latter case is often the case when the source SO is an excimer laser (e.g., based on KrF, ArF, or F2 laser action).

[0137] The beam B is then truncated by the pattern forming apparatus MA held on the pattern forming apparatus stage MT. Having passed through the pattern forming apparatus MA, the beam PB passes through the lens, which focuses the beam B onto the target portion C of the substrate W. The substrate stage WT can be accurately moved, for example, to position different target portions C within the path of the beam B, by means of the second positioning device (and interferometric measuring device). Similarly, the first positioning device can be used to accurately position the pattern forming apparatus MA relative to the path of the beam B, for example, after mechanically retrieving the pattern forming apparatus MA from the pattern forming apparatus library or during scanning. Typically, the movement of the stage MT, WT is achieved by means of long-stroke modules (coarse positioning) and short-stroke modules (fine positioning), which are not explicitly depicted. However, in the case of a stepper (as opposed to a stepping scanning tool), the pattern forming apparatus stage MT may be connected only to the short-stroke actuator, or it may be fixed.

[0138] The tools depicted (and) Figure 1The tools shown (similar or identical) can be used in both modes. In step mode, the pattern forming apparatus stage MT is held essentially stationary, and the entire pattern forming apparatus image is projected onto the target portion C in a single operation (i.e., a single "flash"). The substrate stage WT then shifts along the x and / or y directions, allowing different target portions C to be illuminated by the beam B. In scanning mode, essentially the same applies, except that a given target C is not exposed in a single "flash". Alternatively, the pattern forming apparatus stage MT moves at a rate v in a given direction (the so-called "scanning direction," e.g., the y direction), causing the projected beam B to scan the pattern forming apparatus image; simultaneously, the substrate stage WT moves simultaneously in the same or opposite directions at a rate V = Mv, where M is the magnification of the lens PL (typically M = 1 / 4 or 1 / 5). This allows relatively large target portions C to be exposed without compromising resolution.

[0139] Figure 12 The apparatus 1000 is shown in more detail, including a source collector module SO, an irradiation system IL, and a projection system PS. The source collector module SO is constructed and arranged such that a vacuum environment can be maintained within the enclosure structure 220 of the source collector module SO. A plasma 210 emitting EUV radiation can be formed by a discharge-generated plasma source. EUV radiation can be generated by a gas or vapor, such as xenon, lithium vapor, or tin vapor, wherein a thermal plasma 210 is generated to emit radiation in the EUV range of the electromagnetic spectrum. For example, the plasma 210 is generated by a discharge that causes partial ionization of the plasma. For efficient radiation generation, Xe, Li, Sn vapor, or any other suitable gas or vapor, for example, with a partial pressure of 10 Pa, may be required. In an embodiment, an excited tin (Sn) plasma is provided to generate EUV radiation.

[0140] Radiation emitted by the thermal plasma 210 is transferred from the source chamber 211 to the collector chamber 212 via a gas barrier or contaminant trap 230 (also referred to in some cases as a contaminant barrier or vane trap) optionally positioned in or behind an opening in the source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier, or a combination of a gas barrier and a channel structure. The contaminant trap 230 further indicated herein includes at least a channel structure.

[0141] The source chamber 211 may include a radiation collector CO, which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation passing through the collector CO may be reflected away from the grating spectral filter 240 and then focused along the optical axis indicated by the line "O" at a virtual source point IF. The virtual source point IF is often referred to as the intermediate focus, and the source collector module is arranged such that the intermediate focus IF is located at or near the opening 221 in the enclosure structure 220. The virtual source point IF is an image of the radiative emission plasma 210.

[0142] Subsequently, the radiation passes through the illumination system IL, which may include a faceted field mirror assembly 22 and a faceted pupil mirror assembly 24. The faceted field mirror assembly 222 and the faceted pupil mirror assembly 224 are arranged to provide a desired angular distribution of the radiation beam 21 at the patterning apparatus MA, and to provide desired radiation intensity uniformity at the patterning apparatus MA. When the radiation beam 21 is reflected at the patterning apparatus MA, held by the support structure MT, a patterned beam 26 is formed, and the patterned beam 26 is imaged by the projection system PS via reflective elements 28 and 330 onto the substrate W held by the substrate stage WT.

[0143] The illumination optics unit IL and projection system PS can typically contain more elements than are shown. The grating spectral filter 240 may be optionally present, depending on the type of lithography equipment. Additionally, more mirrors than are shown in the figure may be present, for example, in the projection system PS, in addition to... Figure 12 In addition to the elements shown, there are 1-6 additional reflective elements.

[0144] Collector optics CO (e.g.) Figure 12 The illustrated image is depicted as a nested collector with grazing incidence reflectors 253, 254, and 255, and is only one example of a collector (or collector mirror). The grazing incidence reflectors 253, 254, and 255 are arranged axially symmetrically about the optical axis O, and this type of collector optics CO can be used in conjunction with a plasma source generated by discharge (often referred to as a DPP source).

[0145] Alternatively, the source collector module SO can be as follows: Figure 13This is a portion of the LPP radiation system shown. A laser LA is arranged to deposit laser energy into a fuel, such as xenon (Xe), tin (Sn), or lithium (Li), thereby generating a highly ionized plasma 210 with an electron temperature of tens of eV. High-energy radiation generated during the deexcitation and recombination of these ions is emitted by the plasma, collected by near-normal incident collector optics CO, and focused onto an opening 221 in the enclosure structure 220.

[0146] These embodiments can be further described using the following aspects.

[0147] 1. A method for adjusting manufacturing parameters of a semiconductor device, the method comprising:

[0148] Detect one or more local dimensional deformations of the alignment mark; and

[0149] An alignment signal is generated based on the alignment mark, the alignment signal being weighted based on one or more local dimensional deformations of the alignment mark, and the alignment signal being configured to adjust the semiconductor device manufacturing parameters.

[0150] 2. The method according to aspect 1 further includes adjusting the semiconductor device manufacturing parameters based on the alignment signal.

[0151] 3. The method according to aspect 1 or 2, wherein the semiconductor device manufacturing parameters are platform positions.

[0152] 4. The method according to any one of aspects 1 to 3, wherein detecting the one or more local dimensional deformations comprises:

[0153] The alignment mark is illuminated using radiation, the alignment mark comprising geometric features; and

[0154] Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

[0155] 5. The method according to aspect 4 further comprises: determining, based on the detected one or more phase and / or amplitude offsets, one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on a layer of the semiconductor device structure, or the radiation beam trajectory across the entire geometry.

[0156] 6. A method for generating an alignment signal, the method comprising:

[0157] Detect one or more local dimensional deformations of the alignment mark; and

[0158] The alignment signal is generated based on the alignment mark, and the alignment signal is weighted based on the one or more local dimensional deformations of the alignment mark.

[0159] 7. The method according to aspect 6, wherein detecting the one or more local dimensional deformations comprises:

[0160] The alignment mark is illuminated using radiation, the alignment mark comprising geometric features; and

[0161] Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

[0162] 8. The method according to aspect 7 further comprises: determining one or more of the parameters of the radiation, alignment check locations within the geometry, alignment check locations on layers of the structure, or radiation beam trajectories spanning the entire geometry, based on the detected one or more phase and / or amplitude shifts.

[0163] 9. The method according to any one of aspects 7 to 8, wherein the geometric feature comprises a grating.

[0164] 10. The method according to any one of aspects 7 to 9, wherein detecting the one or more phase and / or amplitude shifts in the reflected radiation from the said geometric feature comprises measuring the phase difference in the reflected radiation of different diffraction orders.

[0165] 11. The method according to any one of aspects 7 to 10, wherein generating the alignment signal comprises:

[0166] Based on the detected one or more phase and / or amplitude shifts, determine one or more regions of the geometric feature that are relatively more symmetrical than other regions of the geometric feature; and

[0167] The portion of the reflected radiation signal corresponding to radiation reflected from one or more of the relatively more symmetrical regions is weighted more heavily than the other portions of the reflected radiation signal.

[0168] 12. The method according to any one of aspects 6 to 11, wherein the alignment mark is included in a layer of a substrate in a semiconductor device structure.

[0169] 13. The method according to aspect 12 further includes adjusting semiconductor device manufacturing parameters based on the alignment signal.

[0170] 14. A non-transitory computer-readable medium having instructions thereon, the instructions causing the computer, when executed by the computer, to:

[0171] Detect one or more local dimensional deformations of the alignment mark; and

[0172] An alignment signal is generated based on the alignment mark, the alignment signal being weighted based on the one or more local dimensional deformations of the alignment mark.

[0173] 15. The non-transitory computer-readable medium according to aspect 14, wherein detecting the one or more local dimensional deformations comprises:

[0174] Controlling the irradiation of the alignment mark using radiation, the alignment mark comprising geometric features; and

[0175] Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

[0176] 16. The non-transitory computer-readable medium according to aspect 15, wherein the instructions further cause the computer to: determine, based on the detected one or more phase and / or amplitude shifts, one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on a layer of the structure, or the radiation beam trajectory across the entire geometry.

[0177] 17. The non-transitory computer-readable medium according to any one of aspects 15 to 16, wherein the geometric features include a grating.

[0178] 18. A non-transitory computer-readable medium according to any one of aspects 15 to 17, wherein detecting the one or more phase and / or amplitude shifts in the reflected radiation from the said geometric feature comprises measuring the phase difference in the reflected radiation of different diffraction orders.

[0179] 19. The method according to any one of aspects 15 to 18, wherein generating the alignment signal comprises:

[0180] Based on the detected one or more phase and / or amplitude shifts, determine one or more regions of the geometric feature that are relatively more symmetrical than other regions of the geometric feature; and

[0181] The portion of the reflected radiation signal corresponding to radiation reflected from one or more of the relatively more symmetrical regions is weighted more heavily than the other portions of the reflected radiation signal.

[0182] 20. A non-transitory computer-readable medium according to any one of aspects 14 to 19, wherein the alignment mark is included in a layer of a substrate in a semiconductor device structure, and the instructions further cause the computer to adjust semiconductor device manufacturing parameters based on the alignment signal.

[0183] 21. A system configured to generate an alignment signal, the system comprising:

[0184] One or more sensors, configured to detect one or more local dimensional deformations of the alignment mark; and

[0185] One or more processors are configured to generate alignment signals based on the alignment marks, the alignment signals being weighted based on the one or more local dimensional deformations of the alignment marks.

[0186] 22. The system according to aspect 21 further includes a radiation source configured to irradiate the alignment mark with radiation, wherein detecting the one or more local dimensional deformations includes:

[0187] Using the radiation source, the alignment mark is irradiated with radiation, the alignment mark including geometric features; and

[0188] The one or more sensors are used to detect one or more phase and / or amplitude shifts in reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

[0189] 23. The system according to aspect 22, wherein the one or more processors are further configured to determine one or more of the parameters of the radiation, alignment check locations within the geometry, alignment check locations on layers of the structure, or radiation beam trajectories spanning the entire geometry based on the detected one or more phase and / or amplitude shifts.

[0190] 24. The system according to any one of aspects 22 to 23, wherein the geometric feature comprises a grating.

[0191] 25. The system according to any one of aspects 22 to 24, wherein detecting the one or more phase and / or amplitude shifts in the reflected radiation from the said geometric feature comprises measuring the phase difference in the reflected radiation of different diffraction orders.

[0192] 26. The system according to any one of aspects 22 to 25, wherein generating the alignment signal comprises:

[0193] Based on the detected one or more phase and / or amplitude shifts, determine one or more regions of the geometric feature that are relatively more symmetrical than other regions of the geometric feature; and

[0194] The portion of the reflected radiation signal corresponding to radiation reflected from one or more of the relatively more symmetrical regions is weighted more heavily than the other portions of the reflected radiation signal.

[0195] 27. The system according to any one of aspects 21 to 26, wherein the alignment mark is included in a layer of a substrate in a semiconductor device structure.

[0196] 28. The system according to aspect 27, wherein the one or more processors are further configured to adjust semiconductor device manufacturing parameters based on the alignment signal.

[0197] The concepts disclosed in this paper can be used to simulate or mathematically model any general imaging system for imaging sub-wavelength characteristics, and are particularly useful in the context of emerging imaging techniques capable of producing increasingly shorter wavelengths. Emerging techniques already in use include EUV (Extreme Ultraviolet) lithography, DUV lithography capable of producing 193 nm wavelengths using ArF lasers, and even DUV lithography capable of producing 157 nm wavelengths using fluorine lasers. Furthermore, to generate photons in this range, EUV lithography can produce wavelengths in the 5 nm to 20 nm range by using synchrotrons or by bombarding materials (solid or plasma) with high-energy electrons.

[0198] While the concepts disclosed herein can be used for imaging on substrates such as silicon wafers, it should be understood that the disclosed concepts can be used with any type of lithography imaging system (e.g., a lithography imaging system for imaging on substrates other than silicon wafers). Furthermore, combinations and sub-combinations of the disclosed elements or components can include individual embodiments.

[0199] The foregoing description is intended to be illustrative and not restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made as described without departing from the scope of the claims set forth below.

Claims

1. A method for adjusting process parameters in semiconductor device manufacturing, the method comprising: Local dimensional deformation is detected by using a first measurement to detect one or more local dimensional deformations of alignment marks, the alignment marks including geometric features; Alignment is determined by using a second measurement different from the first measurement, and an alignment signal is generated based on the alignment mark, the alignment signal being weighted based on the one or more local dimensional deformations of the alignment mark; and The semiconductor device manufacturing process parameters are determined based on one or more phase and / or amplitude asymmetry changes detected in the radiation reflected from the geometry of the alignment mark, the alignment value indicated by the alignment signal, and / or the size of the alignment mark determined by the scattering system. These semiconductor device manufacturing process parameters include: parameters of the radiation, alignment inspection locations within the geometry, alignment inspection locations on layers of the semiconductor device structure, and the radiation beam trajectory across the geometry. The alignment signal is also configured to adjust the semiconductor device manufacturing process parameters.

2. The method according to claim 1, wherein, The semiconductor device manufacturing process parameter is the platform position.

3. The method according to claim 1 or claim 2, wherein, Detecting the one or more local dimensional deformations includes: The alignment mark is illuminated using radiation; and Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

4. The method according to claim 3, further comprising: Based on the detected one or more phase and / or amplitude offsets, determine one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on a layer of the semiconductor device structure, or the radiation beam trajectory across the entire geometry.

5. A method for generating an alignment signal, the method comprising: Local dimensional deformation is detected by using a first measurement to detect one or more local dimensional deformations of alignment marks, the alignment marks including geometric features; Alignment is determined by using a second measurement different from the first measurement, and the alignment signal is generated based on the alignment mark, the alignment signal being weighted based on the one or more local dimensional deformations of the alignment mark; and Semiconductor device manufacturing process parameters are determined based on one or more phase and / or amplitude asymmetry changes detected in the radiation reflected from the geometry of the alignment mark, alignment values ​​indicated by the alignment signal, and / or the size of the alignment mark determined by the scattering system. These semiconductor device manufacturing process parameters include: parameters of the radiation, alignment inspection locations within the geometry, alignment inspection locations on layers of the semiconductor device structure, and radiation beam trajectories across the geometry.

6. The method according to claim 5, wherein, Detecting the one or more local dimensional deformations includes: The alignment mark is illuminated using radiation; and Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

7. The method according to claim 6, further comprising: Based on the detected one or more phase and / or amplitude shifts, determine one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on the layer of the structure, or the radiation beam trajectory across the entire geometry.

8. The method according to any one of claims 6 to 7, wherein, The geometric features include gratings.

9. The method according to claim 6, wherein, Detecting the phase and / or amplitude shift in the reflected radiation from the geometric feature includes measuring the phase difference in the reflected radiation of different diffraction orders.

10. The method according to claim 6, wherein, Generating the alignment signal includes: Based on the detected one or more phase and / or amplitude shifts, determine one or more regions of the geometric feature that are relatively more symmetrical than other regions of the geometric feature; and The portion of the reflected radiation signal corresponding to radiation reflected from one or more of the relatively more symmetrical regions is weighted more heavily than the other portions of the reflected radiation signal.

11. The method according to claim 5, wherein, The alignment marks are included in a layer of the substrate in the semiconductor device structure.

12. The method of claim 11, further comprising adjusting the semiconductor device manufacturing process parameters based on the alignment signal.

13. A non-transitory computer-readable medium having instructions thereon, the instructions causing the computer, when executed by the computer, to: Local dimensional deformation is detected by using a first measurement to detect one or more local dimensional deformations of alignment marks, the alignment marks including geometric features; Alignment is determined by using a second measurement different from the first measurement, and an alignment signal is generated based on the alignment mark, the alignment signal being weighted based on the one or more local dimensional deformations of the alignment mark; and Semiconductor device manufacturing process parameters are determined based on one or more phase and / or amplitude asymmetry changes detected in the radiation reflected from the geometry of the alignment mark, alignment values ​​indicated by the alignment signal, and / or the size of the alignment mark determined by the scattering system. These semiconductor device manufacturing process parameters include: parameters of the radiation, alignment inspection locations within the geometry, alignment inspection locations on layers of the semiconductor device structure, and radiation beam trajectories across the geometry.

14. The non-transitory computer-readable medium according to claim 13, wherein, Detecting the one or more local dimensional deformations includes: Controlling the irradiation of the alignment mark using radiation; and Detect one or more phase and / or amplitude shifts in the reflected radiation from the geometric feature, the one or more phase and / or amplitude shifts corresponding to one or more local dimensional deformations of the geometric feature.

15. The non-transitory computer-readable medium according to claim 14, wherein, The instructions also instruct the computer to: determine, based on the detected one or more phase and / or amplitude offsets, one or more of the parameters of the radiation, the alignment check location within the geometry, the alignment check location on the layers of the structure, or the radiation beam trajectory across the entire geometry.

16. The non-transitory computer-readable medium according to any one of claims 14 to 15, wherein, The geometric features include gratings.

17. The non-transitory computer-readable medium according to claim 14, wherein, Detecting the phase and / or amplitude shift in the reflected radiation from the geometric feature includes measuring the phase difference in the reflected radiation of different diffraction orders.

18. The non-transitory computer-readable medium according to claim 14, wherein, Generating the alignment signal includes: Based on the detected one or more phase and / or amplitude shifts, determine one or more regions of the geometric feature that are relatively more symmetrical than other regions of the geometric feature; and The portion of the reflected radiation signal corresponding to radiation reflected from one or more of the relatively more symmetrical regions is weighted more heavily than the other portions of the reflected radiation signal.

19. The non-transitory computer-readable medium according to claim 13, wherein, The alignment marks are included in a layer of the substrate in the semiconductor device structure, and the instructions further enable the computer to adjust the semiconductor device manufacturing process parameters based on the alignment signals.

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